One of the problems associated with molding boxes, and particularly high aspect ratio boxes in molds, is that a large projected area is required to form the cavity and core which is sufficient to make the mold. Particular shapes within a box require unsupported or undersupported standing mold cores. In conventional molding processes, the unsupported or undersupported standing mold cores are often the weakest point of a mold and the point which first fills or loses tolerance, requiring downtime and repair.
Projected area in a mold is directly related to force required in the molding process.
Problems have for a long time existed and remain in the molding of high aspect ratio containers.
Boxes are usually molded flat with covers and bottoms molded in substantially a similar plane, or in parallel planes having mold cavity areas which extend outward from each other.
Some boxes, such as, for example, containers for video cassettes, are molded with the cover, back and bottom in a single plane. Three side walls of the box, the two spaced lateral walls and the front wall are rigidly molded in upward extension from the bottom. The cover has upward extensions for alignment and engagement with the side walls, usually inside of the side walls, to ensure accurate joining of the cover and side walls. Alignment and detent features in the side walls and in the cover secure the box in closed position. The reduced thickness strips which join the bottom with the back wall and the cover with the back wall form living hinges which fold to complete the form of the cover. The entire box when closed looks like the binding of a book. A problem exists in the molding of such a box, in that the flat molding of the cover, bottom and back requires a high projected area of a mold.
Five-sided sleeves have been made from a single mold using a cavity and core in which the core forms the inner wall surfaces of the five-sided sleeve, and the cavity forms the outer wall surfaces. The deep unsupported core causes a tolerance problem and usually is the first mold part to require maintenance. Even when properly maintained, the high pressures of molding cause lateral diversion of the core, creating tolerance problems.
Problems exist in molding large aspect ratio boxes because of the required areas of the mold, and because of the unsupported or undersupported cores required in the molding of the high aspect ratio boxes.
Typical high aspect ratio boxes are used for holding video cassettes. Other typical high aspect ratio boxes, known as Jewel boxes, are used for holding compact discs. The box has been manufactured in three parts, the box, the cover and an insert. The three-part molding adds expense to the box. That type of high aspect box requires large projected areas in a mold, or requires large unsupported or undersupported cores.
Problems exist in the manufacture of high aspect ratio boxes. Those problems have been of long standing and have not been solved by known molding processes or apparatus.